As an island nation with some 85% of the population residing within 50 km of the coast, Australia faces significant threats into the future from sea level rise. Further, with over 710,000 addresses within 3 km of the coast and below 6-m elevation, the implication of a projected global rise in mean sea level of up to 100 cm over the 21st century will have profound economic, social, environmental, and planning consequences. In this context, it is becoming increasingly important to monitor trends emerging from local (regional) records to augment global average measurements and future projections. The Australasian region has four very long, continuous tide gauge records, at Fremantle (1897), Auckland (1903), Fort Denison (1914), and Newcastle (1925), which are invaluable for considering whether there is evidence that the rise in mean sea level is accelerating over the longer term at these locations in line with various global average sea level time-series reconstructions. These long records have been converted to relative 20-year moving average water level time series and fitted to second-order polynomial functions to consider trends of acceleration in mean sea level over time. The analysis reveals a consistent trend of weak deceleration at each of these gauge sites throughout Australasia over the period from 1940 to 2000. Short period trends of acceleration in mean sea level after 1990 are evident at each site, although these are not abnormal or higher than other short-term rates measured throughout the historical record.

Plot for yourself here a single graph that simultaneously demonstrates the clear observational evidence that

temperature drives CO2

CO2 does not drive temperature

man is not the cause of the rise in CO2 levels

The effect follows the cause; the cause does not follow the effect. Short-term global temperature changes precede CO2 levels by about 1 year as shown by observations, and by 800+ years in ice core data.

Highlights of Humlum et al:► The overall global temperature change sequence of events appears to be from 1) the ocean surface to 2) the land surface to 3) the lower troposphere. ► Changes in global atmospheric CO2 are lagging about 11–12 months behind changes in global sea surface temperature. ► Changes in global atmospheric CO2 are lagging 9.5-10 months behind changes in global air surface temperature. ► Changes in global atmospheric CO2 are lagging about 9 months behind changes in global lower troposphere temperature. ► Changes in ocean temperatures appear to explain a substantial part of the observed changes in atmospheric CO2 since January 1980. ► CO2 released from use of fossil fuels have little influence on the observed changes in the amount of atmospheric CO2, and changes in atmospheric CO2 are not tracking changes in human emissions.

They’re actually not. It’s going to take a long time to seep through the mental block which has accumulated over time, but that was never more than an assumption, for which evidence consistent with it was sought, but falsification was never attempted.

If, however, you actually look at the data, it is clear that temperatures are driving CO2. This plot shows that, since accurate records began, CO2 has evolved to a high degree of fidelity according to the difeq

dCO2/dt = k*(T – To)

where k is a coupling constant, and To is an equilibrium temperature. This is simply a 1st order Taylor series expansion of a continuous transport process for which the rate of change depends on temperature. One such process is the continuous transport of CO2 into downwelling waters and out of the upwelling waters of the thermohaline circulation. With this equation, if you have the starting point and the temperatures in between, you can calculate the CO2 concentration to high accuracy at any time up to the present. You don’t need to know anything about human inputs at all.

The relationship precludes any significant contribution from human emissions. This is because the coupling constant k which matches the variation also precisely matches the trend. Since the rate of human inputs also has a trend, k would have to be reduced to make room for it, but then the variation would not match. The conclusion is necessarily that human inputs are rapidly sequestered, while temperature determines the equilibrium concentration of CO2.

In his inauguration speech, President Obama claimed the "devastating impact of raging fires" was due to man-made climate change. However, two papers published this week find that global fire activity has declined since pre-industrial times. The first paper notes biomass "burning during the past century generally decreased," and the second paper states that "biomass burning emissions over the past millennium exceeded contemporary emissions by up to a factor of 4 for certain time periods." In addition, historical analysis of wildfires around the world shows that since 1950 their numbers have decreased globally by 15%. The President's fear-mongering of a connection between fires and alleged anthropogenic global warming is rejected by "the overwhelming judgement of science."

Abstract

We synthesize existing sedimentary charcoal records to reconstruct Holocene fire history at regional, continental and global scales. The reconstructions are compared with the two potential controls of burning at these broad scales – changes in climate and human activities – to assess their relative importance on trends in biomass burning. Here we consider several hypotheses that have been advanced to explain the Holocene record of fire, including climate, human activities and synergies between the two. Our results suggest that 1) episodes of high fire activity were relatively common in the early Holocene and were consistent with climate changes despite low global temperatures and low levels of biomass burning globally; 2) there is little evidence from the paleofire record to support the Early Anthropocene Hypothesis of human modification of the global carbon cycle; 3) there was a nearly-global increase in fire activity from 3 to 2 ka that is difficult to explain with either climate or humans, but the widespread and synchronous nature of the increase suggests at least a partial climate forcing; and 4) burning during the past century generally decreased but was spatially variable; it declined sharply in many areas, but there were also large increases (e.g., Australia and parts of Europe). Our analysis does not exclude an important role for human activities on global biomass burning during the Holocene, but instead provides evidence for a pervasive influence of climate across multiple spatial and temporal scales.

Abstract.Recent studies based on trace gas mixing ratios in ice cores and charcoal data indicate that biomass burning emissions over the past millennium exceeded contemporary emissions by up to a factor of 4 for certain time periods. This is surprising because various sources of biomass burning are linked with population density, which has increased over the past centuries. We have analysed how emissions from several landscape biomass burning sources could have fluctuated to yield emissions that are in correspondence with recent results based on ice core mixing ratios of carbon monoxide (CO) and its isotopic signature measured at South Pole station (SPO). Based on estimates of contemporary landscape fire emissions and the TM5 chemical transport model driven by present-day atmospheric transport and OH concentrations, we found that CO mixing ratios at SPO are more sensitive to emissions from South America and Australia than from Africa, and are relatively insensitive to emissions from the Northern Hemisphere. We then explored how various landscape biomass burning sources may have varied over the past centuries and what the resulting emissions and corresponding CO mixing ratio at SPO would be, using population density variations to reconstruct sources driven by humans (e.g., fuelwood burning) and a new model to relate savanna emissions to changes in fire return times. We found that to match the observed ice core CO data, all savannas in the Southern Hemisphere had to burn annually, or bi-annually in combination with deforestation and slash and burn agriculture exceeding current levels, despite much lower population densities and lack of machinery to aid the deforestation process. While possible, these scenarios are unlikely and in conflict with current literature. However, we do show the large potential for increased emissions from savannas in a pre-industrial world. This is mainly because in the past, fuel beds were probably less fragmented compared to the current situation; satellite data indicates that the majority of savannas have not burned in the past 10 yr, even in Africa, which is considered "the burning continent". Although we have not considered increased charcoal burning or changes in OH concentrations as potential causes for the elevated CO concentrations found at SPO, it is unlikely they can explain the large increase found in the CO concentrations in ice core data. Confirmation of the CO ice core data would therefore call for radical new thinking about causes of variable global fire rates over recent centuries.

Wednesday, January 30, 2013

Sir, Edward Luce (“Obama must make up for his carbon omissions”, January 21) writes that “the reality of global warming is starker than four years ago – in most respects alarmingly so”. The evidence points in the opposite direction. Since the Intergovernmental Panel on Climate Change produced its last report in 2007, global temperatures, as measured by the HadCRUT3 series, have not increased but have moved sideways, extending the standstill in temperature to more than a decade.

Since carbon dioxide concentrations, seen as the driving force of global warming, have continued unabated, it suggests that something else is at play: the link between CO2 and temperature may not be as strong as assumed in the IPCC model, or other factors such as the sun, oceans or clouds are having a greater influence. Either way, it must call into question the confident assertions based on the prevailing assumptions. As for Arctic ice, its coverage is now back almost exactly to where it was in January 2007.

All this suggests that our climate continues to warm gradually, as it has done since early in the 19th century (which is long before CO2 concentrations started to rise). It may be more plausible to conclude that global warming is around 1°C per century with periods of faster and slower growth fluctuating around the trend, rather than the 3°C predicted by the IPCC. If so, what is happening is interesting but it hardly justifies the epithet alarming.

A paper published today in The Cryosphere finds that the ice volume of global glaciers is 43% less than estimated by the IPCC. According to the author, "the total volume of all glaciers in the world is 0.35 ± 0.07 meter sea level equivalent," as compared to the IPCC estimate of 0.5 meter sea level equivalent. This new paper, along with other recent papers demonstrating that Greenland is resistant to warming, and that ice mass gain in Antarctica is reducing sea levels, collectively demonstrate that IPCC projections of sea level rise are greatly exaggerated.

A. Grinsted1College of Global Change and Earth System Science, Beijing Normal University, Beijing, China2Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, DenmarkAbstract. I asses the feasibility of multi-variate scaling relationships to estimate glacier volume from glacier inventory data. I calibrate scaling laws against volume observations of optimized towards the purpose of estimating the total global ice volume. This is applied individually to each record in the Randolph Glacier Inventory which is the first globally complete inventory of glaciers and ice caps. I estimate that the total volume of all glaciers in the world is 0.35 ± 0.07 m sea level equivalent. This is substantially less than a recent state-of-the-art estimate. Area volume scaling bias issues for large ice masses, and incomplete inventory data are offered as explanations for the difference.

Tuesday, January 29, 2013

A forthcoming paper in Atmospheric Chemistry & Physics finds that tiny 0.07% changes in solar activity over 11-year solar cycles have a "robust" relationship to Northern Hemisphere atmospheric circulation and temperature changes in Europe exceeding 1C. The paper adds to many other peer-reviewed publications demonstrating that tiny changes in solar activity within and between solar cycles can have greatly amplified effects upon climate and temperature.

Y. Brugnara1,2, S. Brönnimann1,2, J. Luterbacher3, and E. Rozanov4,51Institute of Geography, University of Bern, Bern, Switzerland2Oeschger Centre for Climate Change Research, Bern, Switzerland3Department of Geography, Climatology, Climate Dynamics and Climate Change, Justus-Liebig University of Giessen, Giessen, Germany4Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, \newline Davos, Switzerland5Institute for Atmospheric and Climate Science ETH, Zurich, SwitzerlandAbstract. Here we present a study of the 11-yr sunspot cycle's imprint in the Northern Hemisphere atmospheric circulation, using three recently developed gridded upper-air data sets which extend back to the early twentieth century. We find a robust response of the tropospheric late-wintertime circulation to the sunspot cycle, independent from the data set. This response is particularly significant over Europe, but results show that it is not directly related to a North Atlantic Oscillation modulation; instead, it reveals a significant connection to the more meridional Eurasian pattern. The magnitude of mean seasonal temperature changes over the European land areas locally exceeds 1 K in the lower troposphere over a sunspot cycle.

We also analyse surface data to address the question whether the solar signal over Europe is temporally stable for a longer 250 yr period. The results increase our confidence on the existence of an influence of the 11-yr cycle on the European climate, although the signal is much weaker in the first half of the period compared to the second half. The last solar minimum (2005 to 2010), which was not included in our analysis, shows anomalies that are consistent with our statistical results for earlier solar minima.

A new paper published in Astronomy & Astrophysics finds that solar activity may be influenced by gravitational torque from the orbital configuration of the planets. In addition, the authors show that solar activity during the 20th century was at the highest levels of the past 9,400 years.

Top graph shows solar activity in the 20th century was at the highest levels of the past 9,400 years. Time in years before the present shown on horizontal axis.

Context. Understanding the Sun’s magnetic activity is important because of its impact on the Earth’s environment. Direct observations of the sunspots since 1610 reveal an irregular activity cycle with an average period of about 11 years, which is modulated on longer timescales. Proxies of solar activity such as 14C and 10Be show consistently longer cycles with well-defined periodicities and varying amplitudes. Current models of solar activity assume that the origin and modulation of solar activity lie within the Sun itself; however, correlations between direct solar activity indices and planetary configurations have been reported on many occasions. Since no successful physical mechanism was suggested to explain these correlations, the possible link between planetary motion and solar activity has been largely ignored.

Aims. While energy considerations clearly show that the planets cannot be the direct cause of the solar activity, it remains an open question whether the planets can perturb the operation of the solar dynamo. Here we use a 9400 year solar activity reconstruction derived from cosmogenic radionuclides to test this hypothesis.

Methods. We developed a simple physical model for describing the time-dependent torque exerted by the planets on a non-spherical tachocline and compared the corresponding power spectrum with that of the reconstructed solar activity record.

Results. We find an excellent agreement between the long-term cycles in proxies of solar activity and the periodicities in the planetary torque and also that some periodicities remain phase-locked over 9400 years.

Conclusions. Based on these observations we put forward the idea that the long-term solar magnetic activity is modulated by planetary effects. If correct, our hypothesis has important implications for solar physics and the solar-terrestrial connection.

A paper published in Paleoceanography finds another mechanism by which tiny changes in solar activity can cause greatly amplified effects upon the climate via the El Niño Southern Oscillation [ENSO]. According to the authors, the "east-west sea surface temperature gradient along the equator responds almost linearly to solar irradiance forcing [tiny changes in solar activity of 0.2 - 0.5%], with a short lag of about a decade," and "Overall, the sea surface temperature response is of the magnitude required, and is persistent enough, to induce important climatic perturbations worldwide. The results suggest that ENSO may plausibly have acted as a mediator between the Sun and the Earth's climate." In addition, the authors show that solar activity was at the highest levels of the past 10,000 years during the 20th century.

Using a climate model of intermediate complexity, we simulate the response of the El Niño–Southern Oscillation (ENSO) system to solar and orbital forcing over the Holocene. Solar forcing is reconstructed from radiocarbon production rate data, using various scaling factors to account for the conflicting estimates of solar irradiance variability. As estimates of the difference since the Maunder Minimum range from 0.05% to 0.5% of the solar “constant,” we consider these two extreme scenarios, along with the intermediate case of 0.2%. We show that for large or moderate forcings, the low-pass-filtered east-west sea surface temperature gradient along the equator responds almost linearly to irradiance forcing, with a short phase lag (about a decade). Wavelet analysis shows a statistically significant enhancement of the century-to-millennial-scale ENSO variability for even a moderate irradiance forcing. In contrast, the 0.05% case displays no such enhancement. Orbitally driven insolation forcing is found to produce a long-term increase of ENSO variability from the early Holocene onward, in accordance with previous findings. When both forcings are combined, the superposition is approximately linear in the strong scaling case. Overall, the sea surface temperature response is of the magnitude required, and is persistent enough, to induce important climatic perturbations worldwide. The results suggest that ENSO may plausibly have acted as a mediator between the Sun and the Earth's climate. A comparison to key Holocene climate records, from the Northern Hemisphere subtropics and midlatitudes, shows support for this hypothesis.

Monday, January 28, 2013

Research by ASU scientists tracked the number of flu cases by week for the past 16 years. Their studies suggest there is a trend toward earlier and more severe flu seasons with potential link climate change. (Credit: Image courtesy of Arizona State University College of Liberal Arts and Sciences)

Jan. 28, 2013 — The American public can expect to add earlier and more severe flu seasons to the fallout from climate change, according to a research study published online Jan. 28 in PLOS Currents: Influenza.

A team of scientists led by Sherry Towers, research professor in the Mathematical, Computational and Modeling Sciences Center at Arizona State University, studied waves of influenza and climate patterns in the U.S. from the 1997-1998 season to the present.

The team's analysis, which used Centers for Disease Control data, indicates a pattern for both A and B strains: warm winters are usually followed by heavy flu seasons.

"It appears that fewer people contract influenza during warm winters, and this causes a major portion of the population to remain vulnerable into the next season, causing an early and strong emergence," says Towers. "And when a flu season begins exceptionally early, much of the population has not had a chance to get vaccinated, potentially making that flu season even worse."

The current flu season, which is still in high gear in parts of the nation, began early and fiercely. It followed a relatively light 2011-2012 season, which saw the lowest peak of flu since tracking efforts went into effect, and coincided with the fourth warmest winter on record. According to previous studies, flu transmission decreases in warm or humid conditions.

If global warming continues, warm winters will become more common, and the impact of flu will likely be more heavily felt, say the study's authors.

Mathematical epidemiologist Gerardo Chowell-Puente, an associate professor in the School of Human Evolution and Social Change in the College of Liberal Arts and Sciences, adds that the findings could inform preparedness efforts following mild winters: "The expedited manufacture and distribution of vaccines and aggressive vaccination programs could significantly diminish the severity of future influenza epidemics."

The goal of the overarching study is to better grasp the character and trajectory of influenza in all its forms. The study was partially supported by the Multinational Influenza Seasonal Mortality Study, overseen by the National Institutes of Health's Fogarty International Center. Other team members are Rasheed Hameed, Matthew Jastrebski, Maryam Khan, Jonathan Meeks, Anuj Mubayi and George Harris of Northeastern Illinois University.

Abstract: Using CCSM4 climate simulations for 1850–2300 with four different future forcing scenarios, we show that the maximum strength of the Atlantic meridional overturning circulation (MOC) decreases proportionally to the applied CO2 forcing. This weakening of the overturning is caused by a reduction or shut down of North Atlantic (NA) deep convection due to a surface freshening. In the Labrador Sea, the surface freshening is caused by strongly increased liquid freshwater exports from the Arctic, which are largely due to the decrease in the Arctic sea ice cover. In the strongest forcing scenario (RCP8.5), the Arctic becomes summer ice-free by the end of the 21st century and year-round ice-free by the end of the 23rd century. As a result of the associated freshening, all NA deep convection ceases by 2145, which leads to a 72% (18 Sv) decrease of the MOC strength by the end of the simulation in 2300.

A paper published today in the Journal of Climate finds the core IPCC concept of net radiative forcing at the tropopause is "not a useful concept on short timescales because it fails to distinguish between energy absorbed within the [atmosphere itself] and energy absorbed at the [Earth] surface." According to the authors, "This work begs the question: on what timescales and regimes is the radiative forcing at the tropopause a useful concept and when is the response of the system contingent on the vertical structure of the atmospheric forcing?" In other words, the core concept of IPCC climate projections is "not useful" on a short-term basis and it remains unknown if it is useful on a long-term basis. Additionally, the authors find seasonal heating of the atmosphere is primarily due to "top down" direct heating from the Sun of water vapor in the atmosphere, rather than the IPCC concept of "bottom up" heating of the atmosphere from the Earth surface. Note: Satellite data has shown that water vapor is decreasing rather than increasing. Thus, the data shows no evidence of a "positive water vapor feedback" as predicted by IPCC climate models.

Our work demonstrates that the atmospheric response to heating is localized in the vertical and further suggests that the net radiative forcing at the tropopause (i.e. the Solomon et al. 2007, definition of radiative forcing) is not a useful concept on short timescales because it fails to distinguish between energy absorbed within the atmospheric column and energy absorbed at the surface. The vertical structure of atmospheric heating within the troposphere is irrelevant [in the IPCC provided the surface layer is in energetic equilibrium and the troposphere is well mixed in the vertical. Our results demonstrate that neither of these conditions are satis ed in either the climatological or perturbed (2XCO2) seasonal cycles and the atmospheric temperature response depends critically on the vertical distribution of the heating.

This work begs the question: on what timescales and regimes is the radiative forcing at the tropopause a useful concept and when is the response of the system contingent on the vertical structure of the atmospheric forcing? We hope to explore the impact of the vertical structure of atmospheric forcing on the atmospheric temperature response across a myriad of spatio-temporal scales in future work.

Department of Atmospheric Sciences, University of Washington, Seattle, Washington

Abstract

The seasonal cycle of the heating of the atmosphere is divided into a component due to direct solar absorption in the atmosphere, and a component due to the flux of energy from the surface to the atmosphere via latent, sensible, and radiative heat fluxes. Both observations and coupled climate models are analyzed. The vast majority of the seasonal heating of the Northern extratropics (78% in the observations and 67% in the model average) is due to atmospheric shortwave [solar] absorption. In the southern extratropics, the seasonal heating of the atmosphere is entirely due to atmospheric shortwave absorption in both the observations and the models, and the surface heat flux opposes the seasonal heating of the atmosphere. The seasonal cycle of atmospheric temperature is surface amplified in the northern extratropics and nearly barotropic in the southern hemisphere; in both cases, the vertical profile of temperature reflects the source of the seasonal heating.

We examine the change in the seasonal cycle of atmospheric heating in 11 CMIP3 models due to a doubling of atmospheric carbon dioxide from pre-industrial concentrations. We find the seasonal heating of the troposphere is everywhere enhanced by increased shortwave [solar] absorption by water vapor; it is reduced where sea ice has been replaced by ocean which increases the effective heat storage reservoir of the climate system and thereby reduces the seasonal magnitude of energy fluxes between the surface and the atmosphere. As a result, the seasonal amplitude of temperature increases in the upper troposphere (where atmospheric shortwave absorption increases) and decreases at the surface (where the ice melts).

What it would take to persuade me that current climate policy makes sense

I have written about climate change and energy policy for more than 25 years. I have come to the conclusion that current energy and climate policy is probably more dangerous, both economically and ecologically, than climate change itself. This is not the same as arguing that climate has not changed or that mankind is not partly responsible. That the climate has changed because of man-made carbon dioxide I fully accept. What I do not accept is that the change is or will be damaging, or that current policy would prevent it.

For the benefit of supporters of climate change policy who feel frustrated by the reluctance of people like me to accept their assurances, here is what they would need to do to change my mind.

1. I need persuading that the urban heat island effect has been fully purged from the surface temperature record. Satellites are showing less warming than the surface thermometers, and there is evidence that local warming of growing cities, and poor siting of thermometers, is still contaminating the global record. I also need to be convinced that the adjustments made by those who compile the global temperature records are justified. Since 2008 alone, NASA has added about 0.1C of warming to the trend by unexplained “adjustments” to old records. It is not reassuring that one of the main surface temperature records is produced by an extremist prepared to get himself arrested (James Hansen).

2. Despite these two contaminating factors, the temperature trend remains modest: not much more than 0.1 C per decade since 1979. So I would need persuading that water vapour will amplify CO2’s effect threefold in the future but has not done so yet. This is what the models assume despite evidence that clouds formed from water vapour are more likely to moderate than amplify any warming.

3. Nor am I convinced that sulphate aerosols and ocean heat uptake can explain the gap between model predictions and actual observations over the last 34 years. Both are now well understood and provide insufficient excuse for such an underperformance. Negative cloud feedback, leading to total feedbacks being modest, is the more plausible explanation.

4. The one trend that has been worse than expected – Arctic sea ice – is plausibly explained by black carbon (soot), not carbon dioxide. Soot from dirty diesel engines and coal-fired power stations is now reckoned to be a far greater factor in climate change than before; it is a short-lived pollutant, easily dealt with by local rather than global action. So you would need to persuade me that this finding, by explaining some recent climate change, does not further reduce the likely sensitivity of the atmosphere to carbon dioxide. Certainly, it “buys time”.

5. Even the Met Office admits that the failure of the models to predict the temperature standstill of the last 16 years is evidence that natural factors can match man-made ones. We now know there is nothing unprecedented about the level and rate of change of temperature today compared with Medieval, Roman, Holocene Optimum and other post-glacial periods, when carbon dioxide levels did not change significantly, but temperatures did. I would need persuading that natural factors cannot continue to match man-made ones.

6. Given that we know that the warming so far has increased global vegetation cover, increased precipitation, lengthened growing seasons, cause minimal ecological change and had no impact on extreme weather events, I need persuading that future warming will be fast enough and large enough to do net harm rather than net good. Unless water-vapour-supercharged, the models suggest a high probability of temperatures changing less than 2C, which almost everybody agrees will do net good.

7. Nor is it clear that ecosystems and people will fail to adapt, for there is clear evidence that adaptation has already vastly reduced damage from the existing climate – there has been a 98% reduction in the probability of death from drought, flood or storm since the 1920s, for example, and malaria retreated rapidly even as the temperature rose during the twentieth century.

Matt Ridley has been a scientist, journalist and businessman. With BA and DPhil degrees from Oxford University, he worked for the Economist for nine years as science editor, Washington correspondent and American editor, before becoming a self-employed writer and businessman. He is the author of several books, which have sold over 900,000 copies, been translated into 30 languages, been short-listed for nine major literary prizes and won several awards. He is a member of the GWPF’s Academic Advisory Council.

A paper published today in the Journal of Climate finds that climate models have little to no ability to provide skillful forecasts of global surface temperatures on timescales of a decade or more. According to the author, "These results suggest that current coupled model decadal forecasts may not yet have much skill beyond that captured by multivariate red noise." Translation: state-of-the-art climate models that simulate the ocean and atmosphere together [called "coupled models"] offer little predictive ability beyond simulating a random walk [also called "red noise"] over periods of 10 or more years.

CIRES, University of Colorado, and Physical Sciences Division/NOAA Earth System Research Laboratory, Boulder, Colorado

Abstract

The suitability of an empirical multivariate red noise (AR1) model, or linear inverse model (LIM), as a benchmark for decadal surface temperature forecast skill is demonstrated. Constructed from the observed simultaneous and one-year lag covariability statistics of annually-averaged sea surface temperature (SST) and surface (2m) land temperature global anomalies during 1901-2009, the LIM has hindcast skill for leads 2-5 and 6-9 years comparable to and sometimes even better than skill of the CMIP5 model hindcasts initialized annually over the period 1960-2000, and has skill far better than damped persistence (e.g., a local univariate AR1 process). Over the entire post-1901 record, the LIM skill pattern is similar but has reduced amplitude. Pronounced similarity in geographical variations of skill between LIM and CMIP5 hindcasts suggests similarity in their sources of skill as well, supporting additional evaluation of LIM predictability. For forecast leads above 1-2 years, LIM skill almost entirely results from three non-orthogonal patterns, one corresponding to the secular trend and two more, each with about ten year decorrelation time scales but no trend, that represent most of the predictable portions of the Atlantic Multidecadal Oscillation (AMO) and Pacific Decadal Oscillation (PDO) indices, respectively. As found in previous studies, the AMO-related pattern also contributes to multidecadal variations in global mean temperature, and the PDO-related pattern has maximum amplitude in the west Pacific and represents the residual after both interannual and decadal ENSO variability are removed from the PDO time series. These results suggest that current coupled model decadal forecasts may not yet have much skill beyond that captured by multivariate red noise.

Friday, January 25, 2013

A new paper published in Ecology & Evolution finds trees in the Amazon rain forest have tolerated temperatures in the past similar to the [exaggerated] temperature projections of the IPCC for the year 2100. According to the authors, "The remarkably old age of these species suggest that Amazon forests passed through warmth similar to 2100 levels and that, in the absence of other major environmental changes, near-term high temperature-induced mass species extinction is unlikely." The paper adds to severalother peer-reviewed publications showing that alarmist claims of ecosystem collapse or drying up of the Amazon amount to fear mongering, falsehoods, and exaggerations.

Tropical rain forest has been a persistent feature in South America for at least 55 million years. The future of the contemporary Amazon forest is uncertain, however, as the region is entering conditions with no past analogue, combining rapidly increasing air temperatures, high atmospheric carbon dioxide concentrations, possible extreme droughts, and extensive removal and modification by humans. Given the long-term Cenozoic cooling trend, it is unknown whether Amazon forests can tolerate air temperature increases, with suggestions that lowland forests lack warm-adapted taxa, leading to inevitable species losses. In response to this uncertainty, we posit a simple hypothesis: the older the age of a species prior to the Pleistocene, the warmer the climate it has previously survived, with Pliocene (2.6–5 Ma) and late-Miocene (8–10 Ma) air temperature across Amazonia being similar to 2100 temperature projections under low and high carbon emission scenarios, respectively. Using comparative phylogeographic analyses, we show that 9 of 12 widespread Amazon tree species have Pliocene or earlier lineages (>2.6 Ma), with seven dating from the Miocene (>5.6 Ma) and three >8 Ma. The remarkably old age of these species suggest that Amazon forests passed through warmth similar to 2100 levels and that, in the absence of other major environmental changes, near-term high temperature-induced mass species extinction is unlikely.

A forthcoming paper in Climate of the Past reconstructs temperatures from 5 locations in China and finds no statistically significant change in temperature between the beginning of the record 2000 years ago to the end of the record in the year 2000. The paper shows the Medieval Warming Period about 1100 years ago and the Roman Warming Period ~1800 years ago were both warmer than the present.

Q. Ge, Z. Hao, J. Zheng, and X. ShaoInstitute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, 11A Datun Road, Chaoyang District, Beijing 100101, ChinaAbstract. In this paper, we use principal components and partial least squares regression analysis to reconstruct a composite profile of temperature variations in China, and the associated uncertainties, at a decadal resolution over the past 2000 yr. Our aim is to contribute a new temperature time series to the paleoclimatic strand of the Asia2K working group, which is part of the PAGES (Past Global Changes) project. The reconstruction was developed using proxy temperature data, with relatively high confidence levels, from five locations across China, and an observed temperature dataset provided by Chinese Meteorological Administration covering the decades from the 1870s to the 1990s. Relative to the 1870s–1990s climatology, our two reconstructions both show three warm intervals during the 270s–390s, 1080s–1210s, and after the 1920s; temperatures in the 260s–400s, 560s–730s and 970s–1250s were comparable with those of the Present Warm Period. Temperature variations over China are typically in phase with those of the Northern Hemisphere (NH) after 1100, a period which covers the Medieval Climate Anomaly, Little Ice Age, and Present Warm Period. The recent rapid warming trend that developed between the 1840s and the 1930s occurred at a rate of 0.91° C/100 yr [but has since flatlined]. The temperature difference between the cold spell (−0.74° C in the 1650s) during the Little Ice Age, and the warm peak of the Present Warm Period (0.08° C in the 1990s) is 0.82° C at a centennial time scale.

A forthcoming paper in Climate of the Past finds the annual sea ice duration around the west Antarctic Peninsula has markedly increased over the past 7,000 years. The authors attribute the changes to "decreasing mean annual and spring [solar] insolation despite an increasing summer insolation" and to ENSO variability changes. In addition, the authors find the temperature of the Antarctic Peninsula has dropped ~2C over the past 9000 years.

Second graph from top shows decrease in temperature over past 9000 years. Third graph from top shows the proxy for sea-ice and shows a marked increase over the past 7000 years.

J. Etourneau1,*, L. G. Collins1, V. Willmott2, J. H. Kim2, L. Barbara3, A. Leventer4, S. Schouten2, J. S. Sinninghe Damsté2, A. Bianchini4, V. Klein1, X. Crosta3, and G. Massé11Laboratoire d'Océanographie et du Climat: Expérimentations et Approches Numériques, UMR7159, CNRS/UPMC/IRD/MNHN, 4 Place Jussieu, 75252 Paris, France2Royal Netherlands Institute for Sea Research, Department of marine Biogeochemistry and toxicology, 1790 Den Burg, Texel, The Netherlands3EPOC, UMR5805, CNRS, Université Bordeaux 1, Avenue des Facultés, 33405 Talence, France4Colgate University, Department of Geology, 13 Oak Drive, 13346 Hamilton, USA*current address: Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology, 2-15 Natsushima-cho, Yokosuka, 237-0061, JapanAbstract. The West Antarctic ice sheet is particularly sensitive to global warming and its evolution and impact on global climate over the next few decades remains difficult to predict. In this context, investigating past sea ice conditions around Antarctica is of primary importance. Here, we document changes in sea ice presence, upper water column temperatures (0–200 m) and primary productivity over the last 9000 yr BP (before present) in the western Antarctic Peninsula (WAP) margin from a sedimentary core collected in the Palmer Deep basin. Employing a multi-proxy approach, we derived new Holocene records of sea ice conditions and upper water column temperatures, based on the combination of two biomarkers proxies (highly branched isoprenoid (HBI) alkenes for sea ice and TEXL86for temperature) and micropaleontological data (diatom assemblages). The early Holocene (9000–7000 yr BP) was characterized by a cooling phase with a short sea ice season. During the mid-Holocene (~ 7000–3000 yr BP), local climate evolved towards slightly colder conditions and a prominent extension of the sea ice season occurred, promoting a favorable environment for intensive diatom growth. The late Holocene (the last ~ 3000 yr) was characterized by more variable temperatures and increased sea ice presence, accompanied by reduced local primary productivity likely in response to a shorter growing season compared to the early or mid-Holocene. The stepwise increase in annual sea ice duration over the last 7000 yr might have been influenced by decreasing mean annual and spring insolation despite an increasing summer insolation. We postulate that in addition to precessional changes in insolation, seasonal variability, via changes in the strength of the circumpolar Westerlies and upwelling activity, was further amplified by the increasing frequency/amplitude of El Niño-Southern Oscillation (ENSO). However, between 4000 and 2100 yr BP, the lack of correlation between ENSO and climate variability in the WAP suggests that other climatic factors might have been more important in controlling WAP climate at this time.

A paper published today in Atmospheric Chemistry and Physics finds that condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics [including winds]. The paper finds, "The water vapor delivered to the atmosphere via evaporation represents a store of potential energy available to accelerate air and thus drive winds."Obviously, these "major" & "previously overlooked" factors have not been incorporated in climate models, and join the expanding list of major deficiencies of climate models, including internal waves, ocean oscillations, solar amplifying mechanisms, clouds, etc., etc.

A. M. Makarieva1,2, V. G. Gorshkov1,2, D. Sheil3,4,5, A. D. Nobre6,7, and B.-L. Li21Theoretical Physics Division, Petersburg Nuclear Physics Institute, 188300, Gatchina, St. Petersburg, Russia2XIEG-UCR International Center for Arid Land Ecology, University of California, Riverside, CA 92521, USA3School of Environment, Science and Engineering, Southern Cross University, P.O. Box 157, Lismore, NSW 2480, Australia4Institute of Tropical Forest Conservation, Mbarara University of Science and Technology, Kabale, Uganda5Center for International Forestry Research, P.O. Box 0113 BOCBD, Bogor 16000, Indonesia6Centro de Ciência do Sistema Terrestre INPE, São José dos Campos SP 12227-010, Brazil7Instituto Nacional de Pesquisas da Amazônia, Manaus AM 69060-001, BrazilAbstract. Phase transitions of atmospheric water play a ubiquitous role in the Earth's climate system, but their direct impact on atmospheric dynamics has escaped wide attention. Here we examine and advance a theory as to how condensation influences atmospheric pressure through the mass removal of water from the gas phase with a simultaneous account of the latent heat release. Building from fundamental physical principles we show that condensation is associated with a decline in air pressure in the lower atmosphere. This decline occurs up to a certain height, which ranges from 3 to 4 km for surface temperatures from 10 to 30 °C. We then estimate the horizontal pressure differences associated with water vapor condensation and find that these are comparable in magnitude with the pressure differences driving observed circulation patterns. The water vapor delivered to the atmosphere via evaporation represents a store of potential energy available to accelerate air and thus drive winds. Our estimates suggest that the global mean power at which this potential energy is released by condensation is around one per cent of the global solar power – this is similar to the known stationary dissipative power of general atmospheric circulation. We conclude that condensation and evaporation merit attention as major, if previously overlooked, factors in driving atmospheric dynamics.